Sulphur lubricant



gatented June 6, 1933 UNITED STATES PATENT OFFICE VICTOR R. ABBAMS, OF BRUNSWICK, GEORGIA, ASSIGNOR TO ARTHUR H--BAI1I:A.BD, 0F

BRUNSWICK, GEORGIA SI'JLPCHTUR LUBRICANT Ne Drawing.

My invention aims to provide an improved lubricant and method of producing the same, whereby a stable admixture of free sulphur in a liquid vehicle is made available for lubricating purposes.

As my lubricant is of especial value in the art of cutting and machining metals, I will briefly describe the conditions existing when metal is being cut, for example on a turning lathe, milling machine or the like, in order that the desirability of my lubricant may be better understood. It is found upon examination that the chip curls back over the face of the tool,'a-t-a point somewhat back of the cutting edge, and slides away from the cutting edge. The pressure of the chip against the tool face sets up a combination of forces, including compression, tension and shear, which are chiefly responsible for the se aration of the chip metal from the stock eing operated upon, The tool point or edge proper follows along behind the point of separation and functions chiefly to give a smoothing or burnishing elfect to the metal from which the chip has already been separated.

It will thus be evident that the greatest wear on the tool occurs at the point on the face against which the chi bears and that this is behind the edge. t this point the tool is greatly heated owing to the chip sliding along the tool face under the extremely high pressure which necessarily exists and which is chiefly concentrated upon a comparatively small area, resulting in a high degree of friction, and also owing to the compression or deformation whichoccurs in the chip. If a sufficiently high temperature is permitted to build up, the metal may be unduly upset and result in a rough and torn finished article or machined piece. And of course the friction of chip against tool face causes a cup-shaped depression in the latter which weakens the tool and causes it to fail. Consequently the problem presented is to reduce the friction between the chip and tool face and to prevent the generation of heat to a harmfully high degree.

There exists a space or low pressure region bounded by the tool face, the lower side of the Application filed November 26, 1932. Serial No. 644,503.

chip and the surface of the stock being out, and this space or region facilitates the introduction of a lubricant between the chip and the high pressure area on the tool face and also between the stock and the tool edge. In order to serve as an effective lubricant, the substance used should be such as to maintain lubrication between the frictional surfaces. The more completelya film is maintained, the more perfect will be the lubrication. Other conditions being the same, the ability of a lubricant to. maintain a film is largely dependent upon its viscosity at the temperature existing between the bearing surfaces.

Unfortunately for their utility as lubricants at elevated temperatures, commercial oils rapidly decrease'in viscosity with increase in temperature, and with any of the common lubricating oils used for cutting purposes, irrespective of their viscosity at normal temperatures, the'viscosity reaches a very low point when a temperature of 240 to 250 F. has been reached. A measurement of the temperature at the rubbing surface would show a temperature much higher than this. Hence it is that all oils heretofore used in metal cutting have not shown themselves to be much better as lubricants than water or aqueous emulsions. v

Experiments and tests have shown that free sulphur will serve as a superior cutting lubricant, owing to the fact that at the temperatures involved the sulphur is present between the frictional surfaces as a highly viscous liquid. Sulphur melts at a temperature of 235 F., forming at this temperature a thin, straw-colored liquid. As its temperature is raised, the liquid turns darker and becomes more viscous until at about 370 F. it is so viscous that it can hardly be poured. As the temperature is still further raised, the viscosity decreases, but even at a temperature just below its boiling point (832 F.) it is still much more viscous than is cutting oil at even 240 F.

, In addition to this property, which-greatly assists in maintaining a proper lubricating film between the frictional surface, other properties are possessed by free sulphur which renders it superior to oil or similarly tersurface molecular adhesion and otherwise reducing the friction between chip. and tool.

I am aware that there are a number of so-called sulphurized oils now being used as cutting fluids. These contain in solution sulphur compounds, such as sulphonated mineral or lard oils, or contain elemental sulphur in true solution, and in some cases may also contain small amounts of sulphur particles of colloidal size. I.-have discovered that finely divided free sulphur (by which I mean sulphur particles of greater than colloidal size) will itself function as a cutting lubricant which is far superior to any of the cutting lubricants containing sulphur in other forms heretofore used, and that this finely divided'free sulphur'possesses lubric..ting qualities diflerent from. and in addition to, the qualities possessed by sulphur in other forms. This great superiority becomes the more marked at exceptionally high cutting speeds and when difiicultly machinable metals are cut.

From a practical standpoint, the sulphur is advantageously in a liquid vehicle. so that it may be readilyintroduced into the zone of action. If finely divided sulphur (flowers of sulphur) is stirred with oil, water or other liquid vehicles, it will not stay in suspension but will settle out and hence would have to be stirred until almost the time for application in order to be utilized. This is highly inconvenient and therefore impractical as a general proposition.

In accordance with my invention. I am able to prepare stable, mobile. admixtures of finely divided sulphur and liquid vehicles, which may contain as muchor more than 40% of free sulphur. The great bulk of these sulphur particles, as my product is normally prepared, are greatly above colloidal size, and in practice may be of suflicient size as to be easily visible to the naked eye. The liquid vehicle serves principally as a carrier for the sulphur so that it may be introduced to the zone of lubrication, and does not itself function, except perhaps to a slight incidental degree, as a lubricant.

Ordinarily I employ either a low grade, cheap, fuel oil, or simply water, as a vehicle. In order to maintain the sulphur particles, which in practice will be mainly non-col- ,with which I am concerned is not that of merely delaying the settling out of the sulphur particles but that of causing them to be sustained for indefinitely long periods of time so as to obtain stable suspensions of free sulphur. sarily absolute stability but stability in the sense that there is little or no separation or.

settling out of the sulphur particles.

"When I use an oil vehicle for suspending the sulphur particles, I may employ such stabilizers as calcium soap, aluminum stearate, zinc stearate, zinc oleate and other metallic soaps, soaps made from soda or lime and fatty acids, rosin soaps, cup grease (which contains soap) and similar substances. When using a water vehicle, I employ such substances for stabilizers as starch, gums, dextrin, glue, casein, and the like. These stabilizers which I employ may be broadly characterized as being gelforming materials. The water vehicle type of lubricant is claimed specifically in my cogending application, Ser. No. 633,541, filed eptember 16, 1932, as a division in part of my application Ser. No. 603,445, filed April 5, 1932, as a continuation in part of my application Ser. No. 594,741, filed February 23, 1932.

Irrespective of what may be the correct explanation for the stabilizing action, I have found in the course of my work that my sulphur mixtures behave as though comprising a discontinuous gelatinous mass composed of particles of elastic gel in contact with each other and having the inter-spaces containing a liquid, the sulphur particles being distributed between the gel particles and supported thereby. The mass might be termed a fluid gel, or a freely flowing gel, because it acts like a liquid whichmay be readily poured, although largely composed of Upon standing, such mixtures often exude a serum comprised of the liquid contained between the gel particles, forming a layer distinct from the gelatinous mass, the sulphur remaining distributed throughout the latter and stably suspended therein. Gentle agitation or stirring readily causes the serum layer to redistribute itself throughout the gelatinous mass to reform the original mixture.

Having discussed the properties and nature of my stable sulphur suspensions, and the theory so far as it is known to me, so that others skilled in the art may be better able By stable I do not mean neces-.

to proceed in amplifying the list of sulphur stabilizers which. I have specifically named, and in-properly using them, I will now describe in detail several particular embodiments of my invention.

, Ewample 1 Add about 12% of common soap, such as sodium oleate, to about 88% of a petroleum oil, such as a cheap fuel or engine oil, heat to 300 to 350 F. and agitate until solution is effected. Dilute with petroleum until the resulting solution contains about 1% of soap. Allow to cool, preferably without agitation, and add 5% by weight of powdered-commercial sulphur (flowers of sulphur), as by stirring. 'It may also be found to be advantageous to introduce the sulphur before the final dilution. j r

The cooling of the solution results in the formation of a el, which becomes freely flowing upon mixing the sulphur therein. As a result of the mixing, the sulfur-particles are coated with soap and this prevents the sulphur from attacking and corroding the metal surfaces with which the lubricant comes in contact during its storage and during its circulation to and from the point where the cutting tool engages the work.

It will be found that for general cutting conditions, a 5% sulphur mixture will make a suflicicnt lubricant. For lubrication of a hand operated die, for example, only 1% or less by weight of sulphur may be sufficient as the heating is not so great as in the case which is too. thick to be-poured, or may even be a hard cake, by increasing the soap and sulphur percentages. This can be agitated with oil when it is desired to prepare a lubricant and a stable mixture willresult, provided sufficient soap was used in making the cake to insure the proper percentage final mixture.

A Ewample 2 Add 5 to 10 pounds of hydrated lime to 90 pounds of thin mineral oil, say24 B., stir until the lime is thoroughly wetted and distributed in the oil, and add 5 to 10 pounds of rosin oil of ordinary grade. The mixture may be warmed if desired, but the saponification reaction will take place in the old,

in the being largely completed in a few minutes used tomodify the stabilizing power of the mixture, as several different stabilizers may be simultaneously employed.

Example 3 1% to 5% of starch is mixed with water and the whole heated, as by blowing in steam, to the boiling point. The resulting mixture can be thickened or thinned as desired, and from 5% to 25% of powdered sulphur added. A germicide, orfungicide, such as carbolic .acid, may be added to inhibit coagulation of the starch, although the sulphur present may exert a sufficient germicidal effect. I

Ina modification of this example, glue, dextrin, casein (with alkali) and similar substances may be used in place of starch or mixed with it.

A fatty mineral oil may be added to prevent the lubricant from rusting the iron or steel which is exposed to it, and from 1% to 15% of ordinary soap maybe added to increase the wetting ofthe surface to be lubricated.

From the above examples it will be'seen that I have given the art not only a highly superior cutting lubricant but one which is extremely inexpensive to make.

Practical tests have demonstrated that extremely satisfactory results can be secured with my lubricant when operating at high rates of cut. The wear on the tool is much less, thdtool maintains its edges for a'longer period, and a smoother cut is produced.

ests have shown that tools which would not function with cutting media heretofore employed in the art can be satisfactorily used. Friction and heat are reduced and the operation may be speeded up.

-" Two instances are given-which typify the superior results obtained with my lubricant: Drilling M and metal 5" holes drilled in metal. With no lubrication, drill destroyed after 1 holes.

With regular petroleum lubrication, drill destroyed after 10 holes drilled. With sulphur lubricant in water vehicle (starch stabilizer), the drill was merely dulled after 50 holes.

Cutting bolts by vitae/zinc Old machine used and with lard oil (considered one of the finest cutting lubricants) bricant, the machine was speeded up to maximum speed and only one operation required .to give a good thread. One bolt produced per minute as against oneiper five minutes with lard oil lubrication.

My lubricant is not restricted to cutting operations for the severance of metal, but may be applied advantageously to metal spinning, swaging, drawing and die-pressing operations.

The entire composition (including finely powdered sulphur) can also be used as a lubricant for bearings and frictional surfaces generally and are especially advantageous when the temperatures and pressures are abnormally high. Thus it is very satisfactory for use on hot boxes and on heavy bearings where high temperatures are likely to develop, such as hearings on railway cars, journals, etc, and for heavily loaded gears, particularly of the Worm and wheel and hypoid type.

By a freely flowing lubricant is meant a lubricant which will flow freely at normal temperatures through circulating pipes that are used in the machine tool art for applying cutting fluids to the cutting point, and which is not viscous enough to support sulphur in stable suspension by virtue of the apparent bulk viscosityin other words, one which is not a paste or a cake.

The invention is obviously not restricted to the embodiments described, but what is claimed is as follows:

1. A lubricant for use under extreme-pressure and/or high-tcmperature conditions comprising a freely flowing discontinuous gelatinous mass composed of particles of elastic gel in contactwith-each other and having the inter-spaces containing a liquid of the class typified by oil and water, and a suiticient amount of free sulphur particles of greater than colloidal size to function as a. lul'iricating ingredient distributed between the gel particles and Supported thereby.

2. A cutting lubricant comprising a freely flowing discontinuous gelatinous mass compos d of particles of elastic gel incontact with each other and having the interspaccs containing a liquid of the class typified by oil and water and a sutiicient amount of free sulphur particles of greater than colloidal size to function as a lubricating ingredient distributed between the gel particles and supported thereby.

S. The method of preparing a freely flowing lubricant gel containing stably suspended powdered sulphur of greater than colloidal size for use under extreme-pressure and/or high-temperature conditions, comprising hcating and mixing together until solution is effected a liquid vehicle of the class typified by oil and water and a small amount of a suitable elastic-gel-forming substance substantially insoluble therein at normal temperatures, cooling said mixture and allowing a gel to form, and distributing powdered sulphur of greater than colloidal size throughout the gel by mixing therewith, said mixing rendering the gel freely flowing and said gel-forming substance being in sufiicient amount to cause said sulphur to be stably suspended.

l. The method of preparing a freely flowing cutting lubricant gel containing stably suspended powdered sulphur of greater than colloidal size, comprising heating and mix-- ing together until solution is etl'ccted a liquid vehicle of the class typified by oil and water and a small amount of a suitable elastic-gel-forming substance substantially insoluble there n at normal temperatures,cooling said mixture and allowing a gel to form, and distributing powdered sulphur of great er than colloidal size throughout the gel by mixing therewith, said mixing rendering the gel freely flowing and said gel-forming substance be'ng in suliicient amount to cause said sulphur to be stably suspended.

5. The method of preparing a freely flowing lubricant containing stably suspended free sulphur particles of greater than colloi dal size for use under extreme-1n'c ssure and/or high-temperature conditions. comprising heating and mixing together until solution is effected a liquid vehicle of the class typified by oil and water and a small amount of a suitable clastic-gel-forming substance substantiallyinsoluble therein at normal temperatures. cooling said mixture without agitation until a gel is formed. and distributing powdered sulphur of greater than colloidal s'ze throughout the gel by mixing together. said mixing rendering the gel freely flowing and said gel-forming substance being in sufficient amount to cause said sulphur to be stablysuspended.

(l. The method of preparing a freely flowing cutting lubricant containing stably suspended free sulphur particles of greater than colloidal s'zc, comprising heating and mixing together until solution is effected a liquid vehicle of the class typified by oil and water and a small amount of a suitable elastic-gel-forming substance substantially insoluble therein at normal temperatures, cooling said mixture w thout agitation 'until a gel is formed. and distributing powdered sulphur of greater than colloidal size throughout the gel by mixing together. said mixing rendering the gel freely flowing and said gel-forming substance being in sutlicient amount to causesa d sulphur to be stably suspended.

7. A lubricant for use under extreme-pres sure and/or high-temperature conditions comprising a freely flowing discontinuous gelatinous mass composed of particles of -tact with each other and having the interspaces containing oil and a sufficient amount of free sulphur particles of greater than colloidal size, to function as a lubricating ingredient distributed between the gel particles and supported thereby.

9. The method of preparing a freely flowing lubricant gel containing stably suspended powdered sulphur of greater than colloidal size for use under extreme-pressure and/or high-temperature conditions, comprising heating and mixing together until solution is effected an oil vehicle and a small amount of a suitable elastic-gel-forming substance substantially insoluble therein at normal temperatures, cooling said mixture and allowing a gel to form, and distributing powdered sulphur of greater than colloidal size throughout the gel by mixing therewith,sa'id mixing rendering the gel freely flowing and said gel-forming substance being in sufficient amount tocause said sulphur to be stably suspended.

10. The method of preparing a freely flowing cutting lubricant gel containing stably suspended powdered sulphur of greater than colloidal size, comprising heating and mixing together until solution is effected an oil vehicle and a small amount of a suitable elastic-gel-forming substance substantially insoluble therein at normal temperatures,

cooling said mixture and allowing a gel to form, and distributing powdered sulphur of greater than colloidal size throughout the gel by mixing therewith, said mixing rendering the gel freely flowing and said gel-forming substance being in sufficient amount to cause said sulphur to be stably suspended.

11. The method of preparing a freely flowing lubricant containing stably suspended free sulphur particles of greater than colloidal size for use under extreme-pressure and/or high-temperature conditions, comprising heating and mixing together until solution is effected an oil vehicle and a small amount of a suitable elastic-gel-forming substance substantially insoluble therein at nor- 'mal temperatures, cooling said mixture without agitation until a gel is formed, and distributing powdered sulphur of greater than colloidal size throughout the gel by mixing together, said mixing rendering the gel freely flowing and said gel-forming substance being in suflicient amount to cause said sulphur to be stably suspended.

12. The method of preparing a freely flowing cutting lubricant containing stably suspended free sulphur particles of greater than colloidal size, comprising heating and mixing together until solution is effected an oil vehicle and a small amount of a suitable elastic-gel-forming substance substantially in- ,soluble therein at normal temperatures, cooling said mixture without agitation until a gel is formed, and distributing powdered sulphur of greater than colloidal size throughout the gel by mixing together, said mixing rendering the gel freely flowing and said gel-forming substance 'being in sufli cient amount to cause said sulphur to be stably suspended.

13. A cutting lubricant gel freely flowing at ordinary temperatures comprising an oil vehicle gelled with a small amount of soap and containing powdered sulphur of greater ,than colloidal size distributed therethrough in amount to function as a lubricating ingredient and be stably suspended therein.

14. A cutting lubricant gel freely flowing at ordinary temperatures comprising an oil vehicle gelled with a small amount of an alkali-soap and having powdered sulphur of greater than colloidal size distributed there through in amount to function as a lubricating ingredient and be stably suspended therein. 7

15. A cutting lubricant gel freely flowing at ordinary temperatures comprising an oil vehicle and sodium oleate soap and having powdered sulphur of greater than colloidal size distributed therethrough in sufficient amount to function as a lubricating ingredient, said soap being in sufficient amount to cause said sulphur to be stably suspended but not to prevent free flow of said lubricant under normal working conditions.

16. A cutting lubricant gel freely flowing at ordinary temperatures comprising an oil vehicle and heavy metallic soap and having powdered sulphur of greater than colloidal size distributed therethrough in suflicient amount to function as a lubricating ingredient, and stably suspended therein, said soap being in suflicient amount to cause said sulphur to-be stably suspended but not to prevent free flow of said lubricant under normal working conditions.

17. A cutting lubricant gel freely flowing at ordinary temperatures comprising an oil vehicle and a lime rosin oil soap and having powdered sulphur of greater than colloidal size distributed therethrough in suflicient powdered sulphur of greater than colloidal size distributed therethrough and stably suspended therein.

19. A cutting lubricant freely flowing at ordinary temperatures consisting of an oil vehicle and 'an oil and soap gel distributed therethrough and carrying in stable suspension dispersed free sulphur particles of greater than colloidal size in sufficient amount to function. as the lubricating ingredient thereby permitting exceptionally high speed cutting, and said soap serving to minimize the corrosive action of the sulphur when the latter is not-actually being employed to produce lubrication of the cutting tool where it engages the work. r

20. The method of preparing a freely flowing cutting lubricant gel containing powdered sulphur of greater than colloidal size stably suspended in an oil vehicle, comprising mixing and heating together until solution is effected an oil vehicle and a small amount of soap, cooling said mixture and allowing a gel to form, and distributing powdered sulphur of greater than colloidal size throughout the gel by mixing therewith, said mixing rendering the gel freely flowing and said soap being in sufiicient amount to cause said sulphur to be stably suspended.

21. The method of preparing a freely flowing cutting lubricant gel containing powdered sulphur of greater than colloidal size stably suspended in an oil vehicle, comprising mixing and heating together until solution is effected an oil vehicle and a small amount of alkali-soap, cooling said mixture and allowing a gel to form, and distributing powdered sulphur of greater than colloidal size throughout the gel by mixing therewith,

said mixing rendering the gel freely flowing size stably suspended in an oil vehicle, comprising mixing and heating together until solution is effected an oil vehicle and a small amount of heavy metallic soap, cooling said mixture and allowing a gel to form, and distributing powdered sulphur of greater than colloidal size throughout the gel by mixing therewith, said mixing rendering the gel freely flowing and said soap being in sufficient amount to cause said sulphur to be stably suspended.

23; The method of preparing a freely flowing cutting lubricant gel containing powdered sulphur of greater than colloidal size stably suspended in an oil vehicle, comprising mixing and heating together until solution is effected an oil vehicle and a small amount of lime rosin oil soap, cooling said mixture and allowing a gel to form, and discolloidal size throughout the gel by mixing therewith, said mixing rendering the gel freely flowing and said soap being in sufficient amount to cause said sulphur to be stably suspended.

24. The method of preparing a freely flowing cutting lubricant gel containing powdered sulphur of greater than colloidal size stably suspended in an oil vehicle, comprising mixing and heating together until solution is eflected an oil vehicle and a small amount of sodium oleate soap, cooling said mixture and allowing a gel to form, and distributing powdered sulphur of greater than colloidal size throughout the gel by mixing therewith, said mixing rendering the gel freely flowing and said soap being in sufficient amount to cause said sulphur to be stably suspended.

25. The method of preparing a freely flowing cutting lubricant gel containing powdered sulphur of greater than colloidal size stably suspended in an oil vehicle, comprising mixing together a mineral oil and about 1% of sodium oleate soap, agitating at 300350 F. until solution is effected, cooling and allowing a gel to form, and distributing about 5% of powdered sulphur of greater than colloidal size throughout the gel by mixing therewith.

In testimony whereof, I have signed my name to this specification.

VICTOR R. ABRAMS.

tributing powdered sulphur of greater than 

